MOSCOW - President Vladimir Putin said Russia's test-firing of new missiles this week was a response to US plans to build missile defense sites across Europe, and suggested Washington is pursuing an imperialist policy that has triggered a new arms race.

In a clear reference to the United States, Putin harshly criticized "diktat and imperialism" in global affairs and warned Thursday that Russia will keep strengthening its military potential to maintain a global strategic balance.

"It wasn't us who initiated a new round of arms race," Putin said when asked about Russia's missile tests this week at a news conference in Moscow.

In Washington, White House spokesman Gordon Johndroe indicated that Moscow's tests only underscore the US contention that the missile defense system is not aimed at Russia.

"As the Russians are well aware, our missile defense assets in Europe could be easily overwhelmed by existing Russian missile capabilities," he said.

Putin described the tests of a new ballistic missile capable of carrying multiple nuclear warheads and a new cruise missile as part of the Russian response to the planned deployment of new US military bases and missile defense sites in ex-Soviet satellites in eastern Europe.

He assailed the United States and other NATO members for failing to ratify an amended version of the 1990 Conventional Forces in Europe treaty, which limits the deployment of heavy non-nuclear weapons around the continent.

"We have signed and ratified the CFE and are fully implementing it. We have pulled out all our heavy weapons from the European part of Russia to (locations) behind the Ural Mountains and cut our military by 300,000 men," Putin said.

"And what about our partners? They are filling eastern Europe with new weapons. A new base in Bulgaria, another one in Romania, a (missile defense) site in Poland and a radar in the Czech Republic," he said. "What we are supposed to do? We can't just sit back and look at that."

Putin and other Russian officials have repeatedly rejected US assurances that the planned missile defense installations are meant to counter a potential threat from nations such as Iran and pose no danger to Russia.

He reaffirmed his warning that Russia would opt out of the CFE treaty altogether if NATO nations fail to ratify its amended version.

"Either you ratify the treaty and start observing it, or we will opt out of it," Putin said.

In remarks directed at Washington, Putin blasted those "who want to dictate their will to all others regardless of international norms and law."

"It's dangerous and harmful," he added. "Norms of the international law were replaced with political expediency. We view it as diktat and imperialism."

In one of the tests Tuesday, a prototype of Russia's new intercontinental ballistic missile, called the RS-24, was fired from a mobile launcher at the Plesetsk launch site in northwestern Russia and its test warhead landed on target 3,400 miles (5,471.5 kilometers) away on the Kamchatka Peninsula in the far eastern part of the country, officials said.

Deploying a new missile capable of carrying multiple nuclear warheads could allow Russia to maintain nuclear parity with the United States despite having to gradually decommission Soviet-built ICBMs.

The military also tested a new cruise missile based on the existing short-range Iskander missile.

First Deputy Prime Minister Sergei Ivanov, widely seen as a potential Kremlin candidate to succeed Putin, hailed the missile's capability on Thursday.

"It can be used at long range with surgical precision, as doctors say" Ivanov said, according to the ITAR-Tass news agency. "Russia needs this weapon to maintain strategic stability."

ITAR-Tass said Thursday the new cruise missile, R-500, will have a range of up to 310 miles (498.8 kilometers), the limit under a Soviet-era treaty that banned intermediate-range missiles. Putin and other officials have called the treaty outdated but have not said Russia would opt out of it.